Implantable vascular access device

ABSTRACT

An implantable vascular access device includes a housing having an inlet, an outlet, an interior conduit defined therein and a valve positioned between the inlet and the outlet. The valve is subcutaneously manipulated between an open position, in which fluid can flow between the inlet and the outlet, and a closed position in which the valve occludes the interior conduit. The device may include any combination of multiple inlets, outlets and/or interior conduits or chambers and may further include an additional cannula valve. In the preferred embodiment, the housing includes two separate interior conduits suitable for the inflow and outflow of a typical hemodialysis procedure. A method for accessing a vascular structure is provided which includes the steps of surgically implanting a device as described above, connecting one end of a cannula to the outlet of the device and another end of the cannula to a selected vascular structure, subcutaneously manipulating the valve of the device for permitting fluid communication between the inlet of the device and the selected vascular structure and introducing a needle or a needle introduced catheter through the inlet opening to access the selected vascular structure.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to implantable vascular access devicesused in the delivery and/or withdrawal of fluids to and from the bodyand more particularly relates to a self-sealing device which permitsintermittent vascular access.

2. Description of the Prior Art

Conventional vascular access devices are surgically implanted under theskin to allow for intermittent access to a selected vascular structure,such as an artery or a vein, for introducing and/or withdrawing fluidsto and from the selected vascular structure. Typically, such devicesgenerally include an interior chamber having an outlet opening connectedvia a cannula to a vascular structure within the body and a penetrablemembrane which serves as a cover for the interior chamber of the device.The penetrable membrane or septum is comprised of a material, such assilicone rubber, which automatically reseals itself after beingpenetrated by a hypodermic needle or a needle introduced catheter.

In operation, a needle passes through the skin and through thepenetrable membrane into the interior chamber allowing fluid to beinjected into the chamber and expelled through the cannula into theselected vascular structure or, conversely, fluid may be withdrawn. Theadvantages of an implantable device over acute catheter procedures arereduced infection, easier patient maintenance and improved aesthetics.Typical implantable vascular access devices are shown in U.S. Pat. No.5,318,545 to Tucker and U.S. Pat. No. 5,755,780 to Finch, Jr. et al.

The advancement of modem hemodialysis procedures have brought with itthe development of vascular access devices for the purpose of acquiringand returning large quantities of blood for passage through ahemodialysis unit. To facilitate adequate dialysis flow rates,relatively large diameter needles and/or catheters in the range of 14gauge or higher are required. A major drawback of conventional vascularaccess devices, particularly those used in hemodialysis procedures, isthe deterioration of the rubber membranes resulting from repeatedpenetration with such large gauge needles. Additionally, typicalvascular access devices provide for only one needle port resulting inchronic breach of the skin at the same location. This in turn results inincreased skin trauma and possible infection.

Accordingly, it is desirable to provide a vascular access device whichcan withstand multiple insertions with a large diameter needle and whichprovides reduced skin trauma and easier patient maintenance.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a vascular accessdevice which can withstand a high number of large gauge needleinsertions without deterioration.

It is another object of the present invention to provide a vascularaccess device which is easily subcutaneously manipulated and whichprevents the escape of fluids from the device.

It is yet another object of the present invention to provide a vascularaccess device having multiple needle ports thereby reducing the skintrauma caused by repeated needle sticks in the same location.

It is still a further object of the present invention to provide avascular access device suitable for hemodialysis procedures whichincorporates two interior chambers into a single body.

In accordance with one form of the present invention, a vascular accessdevice generally includes a housing having an inlet, an outlet, aninterior conduit defined therein between the inlet and the outlet and avalve positioned along the interior conduit. The valve is movablebetween an open position, in which fluid can flow through the interiorconduit between the inlet and the outlet, and a closed position in whichthe valve occludes the interior conduit. Preferably the valve comprisesan elongate member having a through-hole formed therein which alignswith the interior conduit when the valve is in the open position. One orboth ends of the elongate member protrudes through the housing and ispalpable through the skin of the patient. The elongate member isresiliently urged to its closed position by a spring and is opened bysubcutaneously pressing the end of the member protruding through thehousing.

The device includes a cannula having a proximal end connected to theoutlet of the housing and a distal end connected to a selected vascularstructure. In one embodiment, the distal end of the cannula includes adistal valve positioned within the cannula adjacent the outlet of thecannula. The distal valve is connected to the housing valve and ispreferably a tubular member having an outer wall and an interiorpassage. Along with the housing valve, the distal valve issimultaneously movable within the cannula between an open position inwhich fluid can flow between the housing outlet and the cannula outletthrough the interior passage of the tubular member and a closed positionin which the outer wall of the tubular member occludes the cannulaoutlet. The tubular member is resiliently urged to its closed positionby a spring attached to the cannula.

The present invention may include any combination of multiple inlets,outlets and/or interior conduits. In the preferred embodiment, thehousing includes two separate interior conduits suitable for the inflowand outflow of a typical hemodialysis procedure. The device furtherincludes multiple inlets in fluid communication with each interiorconduit. Several elongate members are moved simultaneously to an openposition by a single push button protruding through the outer surface ofthe housing. Each elongate member includes through-holes which arealigned with respective inlets when the push button is depressed to movethe elongate members to their open position. When the button isreleased, a spring urges the elongate members to their closed positionthereby occluding the inlets. Each interior conduit is in fluidcommunication with an outlet which is connected to a selected vascularstructure by means of a cannula for permitting fluid communicationbetween the vascular structure and the device.

A method for accessing a vascular structure is provided which includesthe steps of surgically implanting a device as described above,connecting one end of a cannula to the outlet of the device and anotherend of the cannula to a selected vascular structure, subcutaneouslymanipulating the valve of the device for permitting fluid communicationbetween the inlet of the device and the selected vascular structure andintroducing a needle or a needle-introduced catheter through the inletopening to access the selected vascular structure.

A preferred form of the vascular access device, as well as otherembodiments, objects, features and advantages of this invention will beapparent from the following detailed description of illustrativeembodiments thereof which is to be read in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are cross-sectional views of the vascular access deviceformed in accordance with the present invention showing the valve in itsclosed and open positions, respectively.

FIGS. 2A and 2B are cross-sectional views of an alternate embodiment ofthe device including a distal cannula valve and showing the valves intheir closed and open positions, respectively.

FIG. 3 a perspective view of the preferred embodiment of the deviceshown in FIGS. 1A and 1B.

FIG. 4 is a cross-sectional view of the device shown in FIG. 3 takenalong the line 4—4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1A and 1B, an implantable vascular access deviceformed in accordance with the present invention is shown. The vascularaccess device 10 is designed to be surgically implanted under the skinand generally includes a housing 11 and a valve 12. The housing 11 andthe valve 12 may be made from any suitable biocompatible materialpossessing sufficient hardness to resist being damaged or gouged byneedles or other devices which will be repeatedly inserted into thedevice. Plastic constructions are advantageous in that they areinexpensive to fabricate utilizing conventional molding techniques andare available in a variety of biocompatible materials. Surgical metals,however, are also suitable.

The housing 11 includes an interior conduit 13 formed therein having aninlet 14 and an outlet 15 extending through an external surface 16 ofthe housing. The outlet 15 may be formed with a cuff 17 to facilitateconnection to a cannula 18. The opposite end (not shown) of the cannulais connected or grafted to a selected vascular structure (e.g. an arteryor a vein) in a conventional manner. The housing 11 also includes aperipheral rim 19 having apertures 20 for securing the device to fasciaunderlying the skin by means of sutures threaded through the peripheralapertures.

The valve 12 preferably comprises an elongate member 21 having atransverse bore or through-hole 22 formed in a body portion 23 thereof.The elongate member 21 further includes a neck portion 24 whichprotrudes through the external surface 16 of the housing. The elongatemember 21 is supported within a bore 25 formed in the housing 11 and isretained within the housing by a retaining clip 26 fixed to the externalsurface 16 of the housing. The valve 12 may be positioned anywhere alongthe interior conduit 13 between the housing inlet 14 and the housingoutlet 15. To maintain the proper orientation of the elongate member 21with respect to the interior conduit 13, the neck portion 24 and/or thebody portion 23 is formed with a non-circular cross-section whichprevents the elongate member from rotating when fitted in close slidingrelationship within the correspondingly sized bore 25 and retaining clip26. A deformable skin 27 fixed to the external surface 16 of the housing11 is preferably provided over the protruding neck portion 24 of theelongate member 21 to prevent tissue ingrowth into the bore 25. Sealingrings (not shown) may also be provided on the elongate member 21 toprevent tissue ingrowth and/or leakage to and from the bore 25.

A spring 28 is positioned within the bore 25 at the end of the elongatemember 21 opposite the neck portion 24. The spring 28 is also made froma biocompatible material and is captured within the bore 25 forresiliently urging the elongate member 21 to its closed position, i.e.,to the right as shown in FIGS. 1A and 1B. Although a spring ispreferred, other biasing devices may also be utilized for resilientlyurging the elongate member 21 to its closed position. For example, thespring 28 may be removed and the bore 25 may be sized to form acompression chamber behind the elongate member 21 wherein the trappedair pressure acts upon the body portion 23 of the elongate member tourge it to its closed position.

In use, the vascular access device 10 is surgically implanted such thatit is entirely subcutaneous. In its normally closed position, the bodyportion 23 of the elongate member 21 blocks or occludes the interiorconduit 13 thereby preventing fluid communication between the inlet 14and the outlet 15. When the protruding neck portion 24 is subcutaneouslydepressed, the elongate member 21 moves to its open position in whichthe transverse through-hole 22 aligns with the interior conduit 13thereby permitting fluid communication between the inlet opening and theoutlet opening 15 through the elongate member. When the valve 12 is inits open position, a needle 29 or a needle-introduced catheter may bepercutaneously inserted through the inlet 14 into the interior conduit13 to introduce or withdraw fluid from the selected vascular structurevia the cannula 18. Once the needle 29 is inserted, the needle will holdthe elongate member 21 in its open position thereby allowing theprotruding end of the body portion 23 to be released. Once the needle 29is removed, the spring 28 will automatically return the elongate member21 to its closed position in which the interior conduit 13 is againoccluded and blood reflux is prevented.

FIGS. 2A and 2B show an alternate embodiment of the device wherein acannula valve 50 is also provided. In this embodiment, the housing 11includes an interior chamber 51 formed therein as opposed to theinterior conduit 13 described above. The housing valve 52 comprises anelongate member 53 having a body portion 54 and a neck portion 55 foraccommodating a spring 56. A transverse bore or through-hole 57 isformed in the body portion 54 to provide fluid communication between theinlet 14 and the interior chamber 51 when the elongate member 53 is inits open position. The elongate member 53 is supported within oppositesupport holes 58 formed in the housing 11 such that both the bodyportion 54 and the neck portion 55 protrude through the housing. Theneck portion 55 and/or the body portion 54 is formed with a non-circularcross-section which when fitted in a correspondingly sized support hole58 maintains the elongate member 53 in its proper orientation. Theelongate member 53 is retained within the housing by a retaining clip 59fixed to the protruding neck portion 55 and deformable skins (not shown)are preferably provided over both protruding portions to prevent tissueingrowth as described above.

The cannula 18 includes a cannula valve 50 positioned within the cannulaadjacent a cannula outlet 60 for selectively permitting fluid flowbetween the housing outlet 15 and the selected vascular structure. Thecannula valve 50 comprises a biocompatible tubular member 61 having anouter wall 62 and an interior passage 63. The tubular member 61 isconnected to the housing valve 12 via a taut wire 64 such thatmanipulation of the housing valve simultaneously activates the cannulavalve. A tension spring 65 is provided at the distal end of the cannula18 to resiliently urge the tubular member 61 to a closed positionwherein the outer wall 62 of the tubular member occludes the cannulaoutlet 60.

In use, depressing the body portion 54 of the elongate member 53 of thehousing valve 52 moves the housing valve to its open position, i.e., tothe left as shown in FIGS. 2A and 2B, thereby simultaneously pulling thecannula valve 50 to an open position via the wire 64. In the openposition, the outer wall 62 of the tubular member 61 no longer occludesthe cannula outlet 60 and fluid may flow through the interior passage 63of the tubular member between the housing outlet 15 and the cannulaoutlet. When the housing valve 12 is released, the tension spring 65returns the tubular member 61 to its closed position whereby the outerwall 62 of the tubular member again occludes the cannula outlet 60.

Referring now to FIGS. 3 and 4, a preferred form of the implantablevascular access device 30 is shown. The multi-port device 30 shown inFIGS. 3 and 4 includes a housing 31 formed with two separate interiorconduits 32, an outlet 33 in fluid communication with each interiorconduit and a plurality of inlets 34. The housing 31 shown in FIGS. 3and 4 includes three external access surfaces 35 each with a pair ofinlets 34 which communicate with a respective interior conduit 32.However, any geometric configuration for the housing, such as additionalaccess surfaces, additional interior conduits or additional inlets maybe utilized.

The multi-port device 30 includes a valve which comprises three elongatemembers 36 each having a spring 37 fixed at one end thereof and a pushbutton 38 with a push plate 39 adjacent the other end. The elongatemembers 36 are formed with transverse through-holes 40, as describedabove, and are slidably supported in longitudinal bores 41 formed in thehousing. The springs 37 are captured between the elongate members 36 andthe bottom walls 42 of the longitudinal bores 41 formed at one end ofthe housing 31. An end cap 43 is fixed to the opposite end of thehousing 31 for retaining the push button 38 and the push plate 39. Theend cap 43 is formed with a recess 44 for retaining the push plate 39and a counter bored opening 45 through which the push button 38protrudes. The push button 38 is formed with a shoulder portion 46 whichis retained by the counter bored opening 45 so that the push button isheld within the end cap 43. The depth of the recess 44 allows the pushplate 39 to travel a predetermined distance when the push button 38 isdepressed.

Operation of the multi-port device 30 is similar to that as describedabove. The springs 37 resiliently urge each of the individual elongatemembers 36 into their normally closed position in which the elongatemembers occlude the inlet openings 34. When the push button 38 issubcutaneously depressed, the elongate members 36 are simultaneouslymoved to their open position by the push plate 39 (i.e., to the right asshown in FIG. 4) wherein the transverse through-holes 40 of the elongatemembers align with respective inlet openings 34. Again, the elongatemembers 36 may be formed with non-circular cross-sections so that theirproper orientation with respect to the inlets 34 is maintained. Once theelongate members 36 are moved to their open position any one or more ofthe inlets 34 may be accessed with a needle for withdrawing orintroducing fluid through the interior chambers 32. In a typicalhemodialysis procedure, an infusion needle is inserted through an inlet34 into one of the interior chambers 32 and an aspiration needle isinserted through another inlet into the other separate chamber. Theinterior chambers are in fluid communication with at least one selectedvascular structure by means of the cannulas 47, as described above.Again, once the needles are inserted the push button 38 may be releasedand upon removing the needle the springs 37 automatically urge theelongate members 36 back to their normally closed position. Preferably,needles should be inserted in corresponding pairs of inlets 34 on thesame access surface 35 so that when the push button 38 is released theremaining elongate members not being accessed will return to theirclosed position.

As a result of the present invention, a multi-port vascular accessdevice is provided which can withstand numerous needle insertionswithout deterioration. Additionally, the multi-port design allows forneedle insertion at different locations on the skin thereby allowing theskin more time to heal before reinsertion of a needle. Furthermore, thedual interior chamber design of the present invention is particularlysuitable for hemodialysis procedures requiring simultaneous inflow andoutflow.

Although the illustrative embodiments of the present invention have beendescribed herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those preciseembodiments, and that various other changes and/or modifications may beeffected therein by one skilled in the art without departing from thescope or spirit of the invention, and it is intended to claim all suchchanges and/or modifications as fall within the scope of the invention.

What is claimed is:
 1. A surgically implantable device for permittingintermittent vascular access comprising: a housing having an inletopening, an outlet opening and an interior conduit defined thereinbetween said inlet opening and said outlet opening; and a manipulatablehousing valve positioned between said inlet opening and said outletopening for selectively permitting fluid communication between saidinlet opening and said outlet opening, said housing valve comprising anelongate member supported within said housing, said elongate memberbeing movable between an open position, in which fluid communication ispermitted between said inlet opening and said outlet opening, and aclosed position, in which said elongate member occludes fluidcommunication between said inlet opening and said outlet opening, atleast one end of said elongate member protruding through an externalsurface of said housing, said at least one end of said elongate memberbeing subcutaneously manipulatable for moving said elongate memberbetween said open and closed positions.
 2. The device as defined inclaim 1, wherein said elongate member includes a transverse bore formedtherethrough, said bore aligning with said interior conduit when saidelongate member is in said open position for permitting fluidcommunication between said inlet opening and said outlet opening.
 3. Thedevice as defined in claim 1, further comprising a biasing deviceadjacent said elongate member for resiliently urging said elongatemember to said closed position.
 4. The device as defined in claim 3,wherein said biasing device comprises at least one spring.
 5. The deviceas defined in claim 3, wherein said biasing device comprises acompression chamber.
 6. The device as defined in claim 1, furthercomprising a cannula having a proximal end connected to said housingoutlet opening and a distal end connectable to a selected vascularstructure.
 7. The device as defined in claim 6, wherein said distal endof said cannula includes a manipulatable distal valve positionedadjacent a cannula outlet for selectively permitting fluid communicationbetween said housing outlet opening and said cannula outlet.
 8. Thedevice as defined in claim 7, wherein said distal valve is connected tosaid housing valve whereby manipulation of said housing valvesimultaneously activates said distal valve.
 9. The device as defined inclaim 7, wherein said distal valve comprises a tubular member having anouter wall and an interior passage, said tubular member being movablewithin said cannula between an open position, in which fluidcommunication is permitted between said housing outlet opening and saidcannula outlet through said interior passage of said tubular member, anda closed position, in which said outer wall of said tubular memberoccludes said cannula outlet thereby preventing fluid communicationbetween said housing outlet opening and said cannula outlet.
 10. Thedevice as defined in claim 9, further comprising a biasing deviceadjacent said tubular member for resiliently urging said tubular memberto said closed position.
 11. A method for accessing a vascular structurecomprising the steps of: surgically implanting a device having an inletopening, an outlet opening, an interior conduit defined therein betweensaid inlet opening and said outlet opening and a valve positionedbetween said inlet opening and said outlet opening said valve comprisingan elongate member supported within said device, said elongate memberbeing movable between an open position, in which fluid communication ispermitted between said inlet opening and said outlet opening, and aclosed position, in which said elongate member occludes fluidcommunication between said inlet opening and said outlet opening, atleast one end of said elongate member protruding through an externalsurface of said device, said valve being manipulatable by depressingsaid at least one end of said elongate member to move said elongatemember to said open position; connecting one end of a cannula to saidoutlet opening and another end of said cannula to a said vascularstructure; manipulating said valve for permitting fluid communicationbetween said inlet opening and said vascular structure; introducing aneedle or needle-introduced catheter through said inlet opening foraccessing said vascular structure.
 12. A surgically implantable devicefor providing intermittent vascular access comprising: a housing havinga plurality of inlet openings, at least one outlet opening and at leastone interior conduit defined therein between said inlet openings andsaid outlet opening; and a manipulatable valve positioned between saidinlet openings and said outlet opening for selectively permitting fluidcommunication between said inlet openings and said outlet opening saidvalve comprising at least one elongate member supported within saidhousing, said elongate member being movable between an open position, inwhich fluid communication is permitted between said inlet openings andsaid at least one outlet opening, and a closed position, in which saidelongate member occludes fluid communication between said inlet openingsand said outlet opening, said housing including a button protrudingthrough an external surface of said housing, said button beingsubcutaneously manipulatable for moving one or more of said elongatemembers between said open and closed positions.
 13. The device asdefined in claim 12, wherein said housing includes two interior conduitsisolated from each other and at least one outlet opening in fluidcommunication with each conduit.
 14. The device as defined in claim 12,wherein said valve comprises at least one elongate member supportedwithin said housing, said elongate member being movable between an openposition, in which fluid communication is permitted between said inletopenings and said at least one outlet opening, and a closed position, inwhich said elongate member occludes fluid communication between saidinlet openings and said outlet opening.
 15. The device as defined inclaim 14, wherein said housing further includes a button protrudingthrough an external surface of said housing, said button beingsubcutaneously manipulatable for moving one or more of said elongatemembers between said open and closed positions.
 16. The device asdefined in claim 12, wherein said at least one elongate member includestwo or more transverse bores formed therethrough, said two or more boresaligning with two or more inlet openings when said elongate member is insaid open position for permitting fluid communication between said twoor more inlet openings and said at least one interior conduit.